Sure thing! We've got 303 and we're gonna multiply it by 86. That's the same as adding 303 to itself 86 times.
Step 1: 0 + 303 = 303
Step 2: 303 + 303 = 606
Step 3: 606 + 303 = 909
Step 4: 909 + 303 = 1212
Step 5: 1212 + 303 = 1515
Step 6: 1515 + 303 = 1818
Step 7: 1818 + 303 = 2121
Step 8: 2121 + 303 = 2424
Step 9: 2424 + 303 = 2727
Step 10: 2727 + 303 = 3030
Step 11: 3030 + 303 = 3333
Step 12: 3333 + 303 = 3636
Step 13: 3636 + 303 = 3939
Step 14: 3939 + 303 = 4242
Step 15: 4242 + 303 = 4545
Step 16: 4545 + 303 = 4848
Step 17: 4848 + 303 = 5151
Step 18: 5151 + 303 = 5454
Step 19: 5454 + 303 = 5757
Step 20: 5757 + 303 = 6060
Step 21: 6060 + 303 = 6363
Step 22: 6363 + 303 = 6666
Step 23: 6666 + 303 = 6969
Step 24: 6969 + 303 = 7272
Step 25: 7272 + 303 = 7575
Step 26: 7575 + 303 = 7878
Step 27: 7878 + 303 = 8181
Step 28: 8181 + 303 = 8484
Step 29: 8484 + 303 = 8787
Step 30: 8787 + 303 = 9090
Step 31: 9090 + 303 = 9393
Step 32: 9393 + 303 = 9696
Step 33: 9696 + 303 = 9999
Step 34: 9999 + 303 = 10302
Step 35: 10302 + 303 = 10605
Step 36: 10605 + 303 = 10908
Step 37: 10908 + 303 = 11211
Step 38: 11211 + 303 = 11514
Step 39: 11514 + 303 = 11817
Step 40: 11817 + 303 = 12120
Step 41: 12120 + 303 = 12423
Step 42: 12423 + 303 = 12726
Step 43: 12726 + 303 = 13029
Step 44: 13029 + 303 = 13332
Step 45: 13332 + 303 = 13635
Step 46: 13635 + 303 = 13938
Step 47: 13938 + 303 = 14241
Step 48: 14241 + 303 = 14544
Step 49: 14544 + 303 = 14847
Step 50: 14847 + 303 = 15150
Step 51: 15150 + 303 = 15453
Step 52: 15453 + 303 = 15756
Step 53: 15756 + 303 = 16059
Step 54: 16059 + 303 = 16362
Step 55: 16362 + 303 = 16665
Step 56: 16665 + 303 = 16968
Step 57: 16968 + 303 = 17271
Step 58: 17271 + 303 = 17574
Step 59: 17574 + 303 = 17877
Step 60: 17877 + 303 = 18180
Step 61: 18180 + 303 = 18483
Step 62: 18483 + 303 = 18786
Step 63: 18786 + 303 = 19089
Step 64: 19089 + 303 = 19392
Step 65: 19392 + 303 = 19695
Step 66: 19695 + 303 = 19998
Step 67: 19998 + 303 = 20301
Step 68: 20301 + 303 = 20604
Step 69: 20604 + 303 = 20907
Step 70: 20907 + 303 = 21210
Step 71: 21210 + 303 = 21513
Step 72: 21513 + 303 = 21816
Step 73: 21816 + 303 = 22119
Step 74: 22119 + 303 = 22422
Step 75: 22422 + 303 = 22725
Step 76: 22725 + 303 = 23028
Step 77: 23028 + 303 = 23331
Step 78: 23331 + 303 = 23634
Step 79: 23634 + 303 = 23937
Step 80: 23937 + 303 = 24240
Step 81: 24240 + 303 = 24543
Step 82: 24543 + 303 = 24846
Step 83: 24846 + 303 = 25149
Step 84: 25149 + 303 = 25452
Step 85: 25452 + 303 = 25755
Step 86: 25755 + 303 = 26058

So, 303*86 = 26058